Elihu thomson



(No Model.) I

E. THOMSON.

' BLIBGTRIO ARC LIGHT. v No. 265,993. Patented Oct. 17, 1882.-

UNITED STATES PATENT OFFICE.

ELIHU THOMSON, OF NEVV BRITAIN, CONNECTICUT.

ELECTRIC-ARC LIGHT.

SPECIFICATION forming part of Letters Patent N0. 265,993, dated October 17, 1882.

To all whom it may concern Be it known that I, ELIHU THOMSON, a citizen of the United States, and a resident ofNew Britaimcounty of Hartford, State of Connecticut, have invented certain new and useful Improvements in Electric-Arc Lights, of which the following is a specification.

My invention relates to an improved regulating magnet system for carbon points of electric lights, by means of which I secure great simplicity and constancy of operation.

Figure 1 is a front elevation of the regulating mechanism of an electric lamp constructed according to myinvention. Fig. 2 is a top view or plan partly in section through the line a; a, Fig. 1.

In Fig. 1, R R is a carbon pencil or carbonsupporting rod, it matters not which. The lower carbon is not shown, being used, as usual, fixed in a suitable support. A direct magnet coil, D, wound with coarse wire, is held in the position shown, and in its interiorth ere passes a bar of iron, M, one end of which is pivoted at P upon an iron frame, F F, of the lamp. The end of the bar M nearest the frame F is allowed to move very closely thereto, while the other end, M, has a range upward to the position shown at min dotted lines, in which upward range it approaches a fixed pole, N, of a shunt-magnet, S, wound with fine wire, and placed in a derived circuit around the carbon at cof the lamp. The bar M has therefore a movement transverselytotheaxisofthecoilD. Theshunt-pole N is preferably curved or tapered to prolong its action and render the attraction of M to it more nearly uniform. The movements of the bar M are utilized to separate and feed the carbons in any well-known manner by clutches or gear-work, or the like.

1 have shown a simple form of lifting and feeding device adapted to feed a carbon pencil in a gradual way. It consists of a shoe, T,- bearing upon the carbon rod 1% laterally, and forcing the said rod over against a grooved roller, G. A bar, Q, connects the magnet M and shoe T together and accommodatesforchanges of position. The horizontal arm L is pivoted to Q, as shown, and also at B, by means of a pin fastened in the frame I and a slot in the arm L. The spring S tends to hold the bar Q and shoe T laterally against the carbon rod 1t Application filed February 16, 1882.

(No model.)

R. However, the length of the bar L is made such that in the position of the parts shown the shoe T is scarcely bearing upon the rod B; but when the magnet M rises to the position shown at m in dotted lines the shoe T is held against the rod 1t and has raised it slightly by virtue of the force of the spring S coming upon the shoe T and bar (3 when raised, the length of the bar L being now insuflicient to hold the shoe T 01f.

The course of the current through the lamp is as follows: Entering at X,it passesthrough the open coil D; thence to therod R at a, where it divides, the main branch passing down through the arc and back at c and out at Y. The derived current or small branch from u. passes through the shunt-magnet coil S and joins the main at I) and out at In Fig. 2, S is the derived-circuit magnet in section; T, the shoe for raising the carbon rod; G, the roller, as before; D, the direct coil, seen from above; 0 C, the base of the regulating mechanism; S, the friction-spring for the shoe T; L L, the arm for holding the shoe T off the rod 1% when the magnet M is down. The direction of the current in each of the coils 1) and S is such that the ends M N or magnetpoles are of like polarity at any moment.

The action of myinvention is as follows: The circulation of current in the coil D magnetizes the bar M, which immediately attracts itself toward the pole N, which is un magnetized, because no cnrrent circulates in the coil S, the carbon pencils of the lamp being supposedly in contact at the stait. The bar M continues to rise until the shoe T, having been drawn against the rod It by the spring S, lills and separates the carbons and establishes an are. This lift and separation continues until the shunt-pole N is sufliciently energized by its coil S to restrain further attraction of the magnet M toward N. This restraint is of course due to the current derived from the arc passing through the coil S and tending to in ake the pole N of the same polarity as that of M near it. By the consumption of the carbons the amount of current diverted to the shunt-magnet S increases, and the magnet M falls away from the pole N in consequence. This continues until the bar or arm L, having arrived at a lower position jams between the pin at B and the bar Q and forces the shoe 1 to release the rod B. This action occurs at intervals more or less small, and a regular feed of the carbon rod 1% is thus effected.

I claim 1. In an electric lamp, a coil traversed by the direct current, surrounding a movable magnetizable bar, pivoted, as described, to an iron frame, in combination with a coil traversed by the derived circuit surrounding a separate fixed core, thepole of which is placed injuxtaposition with the movable bar aforesaid, said movable bar having a transverse play inside the direct coil aforesaid, substantially as described.

2. In an electric lamp, the combination of a fixed shunt-magnet with a movable bar in- ELlIlU THOMSON.

Witnesses:

A. F. SEYMOUR, J. H. (JROMWELL. 

